JPWO2017169603A1 - Transparent conductive film forming composition and transparent conductive substrate - Google Patents

Abstract

The composition for forming a transparent conductive film includes transparent conductive particles, a binder resin, and a solvent, and the solid content concentration of the composition for forming a transparent conductive film is 20 to 50% by mass, The solvent includes a solvent A having a relative evaporation rate of 1 or more when the evaporation rate of butyl acetate is 1, and a solvent B having a relative evaporation rate of less than 1, and a mass ratio of the solvent A to the solvent B. However, Solvent A: Solvent B = 40: 60 to 5:95, and both the solvent A and the solvent B include at least a ketone solvent.

Description

  The present invention relates to a composition for forming a transparent conductive film and a transparent conductive substrate formed using this composition.

  Conventionally, a transparent conductive film has been manufactured by depositing a transparent conductive metal oxide such as tin-containing indium oxide on a substrate by a so-called dry process such as sputtering or vapor deposition. Since the production of the transparent conductive film using such a dry process method is performed under vacuum conditions, an expensive production apparatus is required, the production efficiency is low, and it is not suitable for mass production. Therefore, as a method for replacing the dry process method, a wet process in which a dispersion composition containing transparent conductive particles is applied to form a transparent conductive film is being studied.

  Among transparent conductive particles, tin-containing indium oxide (ITO) particles in which tin is contained in indium oxide are CRTs that are required to be prevented from static electricity and electromagnetic waves because of their high translucency for visible light and high conductivity. It has been used as a suitable material for screens, LCD screens and the like.

  In addition to the tin-containing indium oxide that has been used in the transparent conductive film dry process method, the dispersion composition contains transparent conductive particles such as tin oxide, antimony-containing tin oxide, zinc oxide, and fluorine-containing tin oxide. A coating-type transparent conductive film formed by coating on a material has also been put into practical use.

  As a solvent used for the coating type transparent conductive film, Patent Document 1 proposes hydrocarbons, aromatics, ketones, alcohols, glycols, glycol esters, glycol ethers and the like. Moreover, as a manufacturing method of the coating type transparent conductive sheet provided with the coating type transparent conductive film, Patent Document 1 specifies the amount of residual solvent in the dry coating film as a ratio to the dry film thickness, and the surface electrical resistance value. A coating type transparent conductive sheet having a small change rate and a low haze and a method for producing the same have been proposed.

  In Patent Document 2, the solvent used for the coating type transparent conductive film is limited to at least one selected from ketones and esters, and the relative evaporation rate is 1 when the evaporation rate of butyl acetate is 1 as the solvent. The above-mentioned solvent A and the solvent B having a relative evaporation rate of less than 1 are solvent A: solvent B = 95: 5 to 70:30 in a weight ratio, and the initial surface electrical resistance is satisfied by satisfying limited drying conditions. A composition for a transparent conductive sheet having a low value and excellent in transparency capable of suppressing an increase in the surface electric resistance value over time, and a method for producing a transparent conductive sheet using the composition have been proposed. .

JP 2012-190713 A JP, 2006-207607, A

  However, in general, in a coating composition containing transparent conductive particles, a binder resin, and a solvent, the stability of the composition is insufficient in the solvent system (MEK / toluene) described in the examples of Patent Document 1, Long-term storage may increase the viscosity of the coating composition. Further, when a transparent conductive sheet is formed using such a composition, there is a problem that the stability of the surface electric resistance value is insufficient and the surface electric resistance value increases with time.

  Moreover, the composition for transparent conductive sheets manufactured by said solvent composition described in patent document 2 is based on the composition of predetermined | prescribed solid content concentration by coating systems, such as a gravure coater, a bar coater, and a die coater. In the method of applying full-scale drying after applying the film with shearing force and leveling the coating sufficiently in the initial stage of the constant rate drying period from the material preheating period in which rapid solvent evaporation does not occur, Although the above-described effects can be obtained, as in the spray coater coating method, in the method of spraying a composition having a predetermined solid content concentration in a mist form and applying it without applying a shearing force to the substrate, at the spraying stage, Rapid evaporation of the solvent occurs, surface roughness and haze increase due to leveling failure due to increase in solid content concentration, or poor filling of conductive particles due to short time to dry solidification Thus surface resistivity there is a risk or to increase. In addition, as in the spin coater coating method, a method in which a droplet of a composition having a predetermined solid content concentration is dropped on a substrate that rotates at high speed and is applied by applying a shearing force in the horizontal direction by centrifugal force. Rapid rotation of the solvent occurs due to high-speed rotation, and the surface roughness and haze value increase due to poor spread of the composition and poor leveling due to an increase in solid content concentration, and the time until solidification by drying is short. There was a risk that the surface electrical resistance value would increase due to poor filling of the conductive particles.

  As described above, the coating composition according to the prior art uses a coating method in which the storage stability of the composition and the stability of the surface electrical resistance value are still insufficient, and it is difficult to sufficiently level the composition. In some cases, the transparent conductive film may not have sufficiently satisfactory characteristics in terms of surface roughness, haze value, and surface electrical resistance value.

  The present invention is excellent in storage stability, can reduce the surface roughness and haze value of the transparent conductive film formed on the transparent substrate, and can sufficiently reduce the surface electric resistance value, regardless of the coating method. Provided is a composition for forming a transparent conductive film.

  The composition for forming a transparent conductive film of the present invention is a composition for forming a transparent conductive film comprising transparent conductive particles, a binder resin, and a solvent. The solid content concentration is 20 to 50% by mass, and the solvent includes a solvent A having a relative evaporation rate of 1 or more and a solvent B having a relative evaporation rate of less than 1 when the evaporation rate of butyl acetate is 1. The mass ratio of the solvent A and the solvent B is solvent A: solvent B = 40: 60 to 5:95, and both the solvent A and the solvent B include at least a ketone solvent. It is characterized by including.

  The transparent conductive substrate of the present invention is a transparent conductive substrate including a transparent substrate and a transparent conductive film disposed on the transparent substrate, and the transparent conductive film of the present invention is It was formed using the composition for transparent conductive film formation.

  According to the present invention, the storage stability is excellent, the surface roughness and haze value of the transparent conductive film formed on the transparent substrate are small, and the surface electrical resistance value is sufficiently low regardless of the coating method. A possible composition for forming a transparent conductive film and a transparent conductive substrate formed using the composition can be provided.

  In the present invention, a film immediately after a transparent conductive film forming composition containing transparent conductive particles, a binder resin and a solvent is applied on a transparent substrate is used as the transparent conductive coating film, and the solvent of the transparent conductive coating film is used. The evaporated and dried film is referred to as a transparent conductive film, and the film including the transparent substrate and the transparent conductive film is referred to as a transparent conductive substrate. Moreover, the composition for forming a transparent conductive film may be simply referred to as a composition.

<Transparent conductive film forming composition>
The composition for forming a transparent conductive film is obtained by preparing transparent conductive particles and a binder resin by dispersing them in a solvent. The solid content concentration of the composition for forming a transparent conductive film is in the range of 20 to 50% by mass. The solid content concentration is preferably 25 to 45 mass%, more preferably 30 to 40 mass%.

  When the solid content concentration of the composition for forming a transparent conductive film is less than 20% by mass, the amount of solvent in the composition for forming a transparent conductive film increases, and therefore, it is relatively easy to evaporate as described later. Solvent A (solvent having a relative evaporation rate of 1 or more when the evaporation rate of butyl acetate is 1) and solvent B (relative evaporation rate of 1 when the evaporation rate of butyl acetate is 1) are relatively difficult to evaporate. Less solvent), the amount of solvent to be evaporated and dried from the transparent conductive coating film is large. Therefore, the convection of the composition accompanying the evaporation of the solvent reduces the filling property of the transparent conductive particles, and the transparent conductive property Since the contact between the particles decreases, the surface electrical resistance value may not be sufficiently lowered. In addition, the surface roughness may increase, or the amount of residual solvent in the transparent conductive film may increase.

  When the solid content concentration exceeds 50 mass%, the amount of the solvent is small, so that the dispersion of the composition for forming a transparent conductive film becomes insufficient, and the dispersion stability is lowered, so that the storage stability of the composition is lowered. Moreover, there is a risk of causing leveling defects.

  In the composition for forming a transparent conductive film having a solid content concentration of 20 to 50% by mass, in other words, in the composition for forming a transparent conductive film of the present invention containing 50 to 80% by mass of the solvent, the solvent has an evaporation rate. By using a solvent in which different solvents A and B are mixed, the solvent A is relatively easily evaporated when the transparent conductive film-forming composition is applied to a transparent substrate and dried to form a transparent conductive film. Thus, the amount of residual solvent in the transparent conductive film can be reduced. In addition, the solvent B, which is relatively hard to evaporate, gradually evaporates as compared to the solvent A, which is easy to evaporate. Therefore, the filling property is improved, and the contact between the transparent conductive particles is increased, whereby the surface electrical resistance value of the transparent conductive film can be sufficiently reduced.

  When mixing the solvent A, which is relatively easy to evaporate, and the solvent B, which is relatively difficult to evaporate, the mass ratio of the solvent A and the solvent B is as follows: solvent A: solvent B = 40: 60-5 : 95 range. By setting it in the above range, the solid content concentration of the composition is likely to increase as in the spray coater coating method and the spin coater coating method, and the evaporation rate of the solvent is moderated even in a coating method in which the time to dry solidification is short. It is possible to suppress a rapid increase in the solid content concentration as compared with the prior art composition, and it is possible to ensure a long time to dry solidification. As a result, the leveling property and spreadability of the composition are improved, the surface roughness and haze value of the transparent conductive film can be reduced, and the uniform deposition and filling of the transparent conductive particles proceeds sufficiently, that is, Fillability is improved and a transparent conductive film having a low surface electric resistance value can be realized. In addition, the amount of residual solvent in the transparent conductive film can be made equal to or less than that of the prior art composition.

  If the proportion of the solvent A, which is relatively easy to evaporate in the entire mixed solvent, is less than 5 parts, the wettability of the solvent with respect to the conductive particles may be reduced, and it may be difficult to maintain dispersion stability. . Moreover, the drying property of the transparent conductive coating film immediately after coating becomes extremely slow, and there is a possibility that the amount of residual solvent in the transparent conductive coating film increases. Further, when the proportion of the solvent A that is relatively easy to evaporate in the entire mixed solvent exceeds 40 parts, the amount of the solvent A that is relatively easy to evaporate is too much, so that the spray coater coating method and the spin coater coating method are used. In a coating method in which the solid content concentration of the composition is likely to increase and the time until drying and solidification is short, the surface roughness and haze value increase due to poor spread of the composition and poor leveling due to the increase in solid content concentration, There is a possibility that the surface electrical resistance value may increase due to poor filling of the conductive particles due to the short time until drying and solidification. The ratio of the solvent A in the entire mixed solvent is preferably in the range of 10 to 30 parts.

  Both the solvent A and the solvent B include at least a ketone solvent. Here, the content of the ketone solvent in the solvent A is preferably 90% by mass or more based on the total amount of the solvent A. By setting it as the said range, the dispersibility of a composition can improve and it can be set as the composition for transparent conductive film formation excellent in storage stability. When the content of the ketone solvent in the solvent A is less than 90% by mass with respect to the total amount of the solvent A, the dispersibility of the composition is lowered, and the storage stability of the composition may be lowered. The content of the ketone solvent in the solvent A is more preferably 95% by mass or more based on the total amount of the solvent A.

  The content of the ketone solvent in the solvent B is preferably 70% by mass or more with respect to the total amount of the solvent B. By setting the above range, the dispersibility of the composition is improved, the evaporation rate of the solvent at the time of application is moderated, and the rapid increase in the solid content concentration can be suppressed, so that the leveling property and spreadability of the composition are improved. And the surface roughness and haze value of the transparent conductive substrate can be reduced. In addition, since the time until drying and solidification can be secured for a long time, uniform deposition and filling of transparent conductive particles sufficiently proceeds, that is, the filling property is improved, and a transparent conductive substrate having a low surface electric resistance value is obtained. be able to. When the content of the ketone solvent in the solvent B is less than 70% by mass with respect to the total amount of the solvent B, the dispersibility of the composition is lowered, and the storage stability of the composition may be lowered. The content of the ketone solvent in the solvent B is more preferably 80% by mass or more with respect to the total amount of the solvent B.

  The content of the ketone solvent in the solvent A is 90% by mass or more with respect to the total amount of the solvent A, and the content of the ketone solvent in the solvent B is 70% by mass or more with respect to the total amount of the solvent B. Then, the solvent A and the solvent B may contain a solvent other than the ketone solvent.

(solvent)
As the solvent, a solvent A having a relative evaporation rate of 1 or more when the evaporation rate of butyl acetate is 1, and a solvent B having a relative evaporation rate of less than 1 are used. Here, the relative evaporation rate is a relative evaporation rate when the evaporation rate of butyl acetate is 1, and it means that the larger the value, the easier the evaporation, and the smaller the value, the harder the evaporation.

  Both of the solvent A and the solvent B include at least a ketone solvent.

  As the ketone solvent classified into the solvent A having a relative evaporation rate of 1 or more, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK) and the like can be used. Examples of the ketone solvent classified as the solvent B having a relative evaporation rate of less than 1 include cyclopentanone, cyclohexanone, cycloheptanone, diisobutyl ketone (DIBK), 2-heptanone, methyl isoamyl ketone, and methyl-n. -Propyl ketone, isophorone, etc. can be used.

  As long as the relative evaporation rate when the evaporation rate of butyl acetate in the solvent A is 1 or more and the relative evaporation rate when the evaporation rate of butyl acetate is 1 in the solvent B is less than 1, the above The solvent A and the solvent B may be mixed with alcohol-based, ester-based, aliphatic-based, aromatic-based, glycol-based, ether-based, or glycol-ether-based solvents in addition to the above-mentioned ketone-based solvents. When these solvents are used by mixing with a ketone solvent, it is desirable to add them to such an extent that the dispersibility of the conductive fine particles is not impaired.

  Examples of the solvent classified as the solvent A other than the ketone solvents include methyl alcohol, ethyl alcohol, isopropyl alcohol, ethyl acetate, isopropyl acetate, normal propyl acetate, tetrahydrofuran, hexane, heptane, cyclohexane, and toluene. In addition to the above-mentioned ketone solvents, the solvents classified as solvent B include normal propanol, normal butanol, ethyl lactate, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether acetate, ethylene glycol mono Examples include butyl ether, diethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, 1,4-dioxane, xylene and the like.

(Transparent conductive particles)
The transparent conductive particles are not particularly limited as long as the particles have both transparency and conductivity. For example, conductive metal oxide particles and conductive nitride particles can be used. Examples of the conductive metal oxide particles include metal oxide particles such as indium oxide, tin oxide, zinc oxide, and cadmium oxide. Also, conductive metal oxide particles doped with tin, antimony, aluminum, gallium, with one or more metal oxides selected from the group consisting of indium oxide, tin oxide, zinc oxide and cadmium oxide as main components, For example, tin-containing indium oxide (ITO) particles, antimony-containing tin oxide (ATO) particles, aluminum-containing zinc oxide (AZO) particles, gallium-containing zinc oxide (GZO) particles, and conductive metal oxide particles obtained by replacing ITO with aluminum. Can be used. Among these, ITO particles are particularly preferable from the viewpoint of excellent transparency and conductivity. In addition, from the viewpoint of conductivity, in the ITO particles, the amount of tin added to the entire ITO is preferably in the range of 1 to 20% by mass in terms of tin oxide. The conductivity is improved by adding tin to ITO. However, when the amount of tin added is less than 1% by mass, the improvement in conductivity tends to be poor. Tend to be less.

  The transparent conductive particles preferably have an average primary particle diameter in the range of 10 to 200 nm. When the average primary particle diameter is less than 10 nm, it is considered that the dispersion treatment becomes difficult and the particles are easily aggregated, but the haze increases and the optical properties tend to be inferior. In addition, when the average primary particle diameter exceeds 200 nm, it seems to be due to the scattering of visible light by the particles, but the haze tends to increase. Here, the average primary particle diameter is, for example, at least 100 particles after observing and measuring the particle diameter of each particle using an electron microscope on the surface or cross section of the transparent conductive film formed on the transparent substrate. The average particle diameter is the average of the particle diameters.

(Binder resin)
It is preferable that content of the said binder resin contained in the said composition for transparent conductive film formation is the range of 5-18 mass parts with respect to 100 mass parts of transparent conductive particles. When the content of the binder resin is less than 5 parts by mass, the effect of improving the coating film strength tends to be poor, and when the content of the binder resin exceeds 18 parts by mass, the surface electrical resistance value tends to increase. There is a possibility that good conductivity cannot be obtained.

  Although it does not specifically limit as said binder resin, Resin whose glass transition temperature is the range of 30-120 degreeC is preferable. By using a resin having a glass transition temperature in the range of 30 to 120 ° C. as the binder resin, the transparent conductive film can have appropriate flexibility. As the binder resin, for example, a thermoplastic resin having a glass transition temperature of 30 to 120 ° C. or a radiation curable resin having a glass transition temperature of 30 to 120 ° C. can be used. The said binder resin may be used independently or may be used in combination of 2 or more type. Here, the measurement of the glass transition temperature can be performed in accordance with Japanese Industrial Standard (JIS) K7121 using a DSC method based on so-called thermal analysis.

  As a thermoplastic resin whose said glass transition temperature is the range of 30-120 degreeC, an acrylic resin or a polyester resin etc. can be used, for example.

  Examples of the acrylic resin include “Dianar BR-60”, “Dianar BR-64”, “Dianar BR-75”, “Dianar BR-77”, “Dianar BR” manufactured by Mitsubishi Rayon Co., Ltd. −80 ”,“ Dianar BR-83 ”,“ Dianar BR-87 ”,“ Dianar BR-90 ”,“ Dianar BR-95 ”,“ Dianar BR-96 ”,“ Dianar BR-100 ” ”,“ Dianar BR-101 ”,“ Dianar BR-105 ”,“ Dianar BR-106 ”,“ Dianar BR-107 ”,“ Dianar BR-108 ”,“ Dianar BR-110 ”, “Dianar BR-113”, “Dianar BR-122”, “Dianar BR-605”, “Dianar MB-2539”, “Dianar MB-2389”, “Dianar MB-2487”, “Dianar MB-2660”, “Dianar MB-2952”, “Dianar MB-3015”, “Dianar MB-7033”, etc. .

  Examples of the polyester resin include “Byron 200”, “Byron 220”, “Byron 226”, “Byron 240”, “Byron 245”, “Byron 270”, “Byron 280”, “Byron” manufactured by Toyobo Co., Ltd. 290 ”,“ Byron 296 ”,“ Byron 660 ”,“ Byron 885 ”,“ Byron GK110 ”,“ Byron GK250 ”,“ Byron GK360 ”,“ Byron GK640 ”,“ Byron GK880 ”and the like.

Although it does not specifically limit as said radiation curable resin whose said glass transition temperature is the range of 30-120 degreeC, For example, an acrylate monomer, a methacrylate monomer, an epoxy acrylate, a urethane acrylate, a polyester acrylate, an acrylic oligomer etc. are mentioned. Specifically, isobornyl acrylate, 2-phenoxyethyl methacrylate, tripropylene glycol diacrylate, diethylene glycol diacrylate, ethoxylated bisphenol A dimethacrylate, trimethylolpropane triacrylate, dipentaerythritol pentaacrylate, etc. may be used. it can. Here, the glass transition temperature of the radiation curable resin is, for example, an ultraviolet polymerization initiator such as 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1 with respect to 100 parts by mass of the resin. -It is preferable to use the measurement value after the radiation curing treatment obtained by adding 5 parts by mass of ON and irradiating with ultraviolet rays at 500 mJ / cm ² .

  When a radiation curable resin is used as the binder resin, the curing treatment may be performed by radiation such as ultraviolet rays, electron beams, and β rays. Among these, it is convenient to use ultraviolet rays. In this case, an ultraviolet polymerization initiator may be further added to the radiation curable resin. As the ultraviolet polymerization initiator, the following can be used. For example, benzoin isopropyl ether, benzophenone, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone, 2,4-diethylthioxanthone, methyl o-benzoylbenzoate, 4,4-bisdiethylaminobenzophenone, 2, 2-diethoxyacetophene, benzyl, 2-chlorothioxanthone, diisopropylthioxanthone, 9,10-anthraquinone, benzoin, benzoin methyl ether, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl -Propiophenone, 4-isopropyl-2-hydroxy-2-methylpropiophenone, α, α-dimethoxy-α-phenylacetone and the like can be used. The said ultraviolet polymerization initiator may be used independently and may be used in combination of 2 or more type.

  The ultraviolet polymerization initiator is preferably added in an amount of 1 to 20 parts by mass with respect to 100 parts by mass of the radiation curable resin. When the addition amount of the ultraviolet polymerization initiator is less than 1 part by mass, it is considered that the curability of the resin is inferior, but the strength of the transparent conductive film tends to be inferior. Moreover, when the addition amount of the said ultraviolet polymerization initiator exceeds 20 mass parts, although it seems that bridge | crosslinking does not fully advance, it exists in the tendency for the intensity | strength of a transparent conductive film to be inferior.

  Moreover, you may use thermosetting resins, such as an epoxy resin, as resin whose glass transition temperature is the range of 30-120 degreeC.

(Other additives)
The composition for forming a transparent conductive film may contain a dispersant, a plasticizer, an antistatic agent and the like in addition to the transparent conductive particles and the binder resin.

  As the dispersant, a dispersant containing at least an anionic functional group is preferably used, and a polyester resin containing an anionic functional group and an acrylic resin containing an anionic functional group are more preferably used. For example, carboxylic acid-containing acrylic resins, acid-containing polyester resins, acid and base-containing polyester resins, and the like can be used. Specifically, “Dianar MR-2539”, “Dianar MB-2389”, “Dianar MB-2660”, “Dianar MB-3015”, “Dianar BR-84” manufactured by Mitsubishi Rayon Co., Ltd., etc. Or “Solspurs 3000”, “Solspurs 21000”, “Solspurs 32000”, “Solspurs 36000”, “Solspurs 41000”, “Solspurs 43000”, “Solspurs 44000”, “Solspurs 45000” manufactured by Abyssia A commercially available product such as “Solspers 56000” can be used.

  The preparation method of the said composition for transparent conductive film formation should just disperse | distribute transparent conductive particle and binder resin in a solvent, and the dispersion | distribution method is not specifically limited, respectively. For example, a dispersion process using a bead mill such as a sand grind mill, an ultrasonic disperser, a three roll mill, or the like can be mentioned, but a dispersion process using a bead mill is preferable from the viewpoint of better dispersibility.

<Transparent conductive substrate>
The transparent conductive substrate includes a transparent substrate and a transparent conductive film disposed on the transparent substrate, and the transparent conductive film is formed using the above-described composition for forming a transparent conductive film. ing. The total light transmittance of the transparent conductive substrate is preferably 75% or more, and more preferably 85% or more. Further, the haze value is preferably 2% or less, and more preferably 1% or less. By setting the total light transmittance and haze value of the transparent conductive substrate to the above ranges, the transparent conductive substrate can be selected from, for example, a touch panel, a light control film electrode, a transparent surface heating element, a display antistatic film, It can be suitably used for a transparent conductive substrate for an electromagnetic shielding material.

(Transparent substrate)
The transparent substrate is not particularly limited as long as it is made of a transparent material having translucency. For example, polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyolefins; cellulose resins such as cellulose triacetate; amide resins such as nylon and aramid; polyether resins such as polyphenylene ether and polysulfone ether; polycarbonate resins; A film or a substrate made of a material such as polyamide resin; polyimide resin; polyamideimide resin; aromatic polyamide resin; can be used. The transparent substrate may be formed using glass, ceramics, or the like. In that case, inorganic glass or organic glass (polymer substrate) can be used as the glass material. In the case of a film or substrate, the thickness of the transparent substrate is preferably in the range of 3 to 300 μm, and more preferably in the range of 25 to 200 μm. When the transparent conductive film forming composition is applied using a spray method, a spin method or the like, the transparent substrate is preferably formed of glass, ceramics, or the like.

  In the present invention, the term “transparent” means that the total light transmittance measured in accordance with JIS K7161: 1997 is 75% or more.

  Additives such as an antioxidant, a flame retardant, an ultraviolet absorber, a lubricant, and an antistatic agent may be added to the transparent substrate. Furthermore, in order to improve adhesion with the transparent conductive film formed on the transparent substrate, an easy-adhesive layer (for example, a primer layer) is provided on the substrate surface, or surface treatment such as corona treatment or plasma treatment. Can be done.

  The method for forming the transparent conductive substrate by applying the transparent conductive film forming composition to the transparent substrate is not particularly limited as long as it is a coating method capable of forming a smooth coating film. For example, a coating method such as a gravure roll method, a micro gravure roll method, a spray method, a spin method, a knife method, a kiss method, a squeeze method, a reverse roll method, a dip method, or a bar coating method can be used. In particular, the composition of the present invention is preferably used in a coating method in which the solid content concentration of the composition tends to increase and the time until drying and solidification is short, such as a spray coater coating method and a spin coater coating method.

  As a method for drying the coating film, hot air may be applied from the transparent conductive coating film side or from the transparent substrate side. Moreover, you may make a heat source contact the transparent substrate side directly. Moreover, you may dry a transparent conductive coating film by a non-contact method with a heat source using an infrared heater, a far-infrared heater, etc. Furthermore, you may dry naturally in the space where temperature and humidity were controlled.

  Hereinafter, the present invention will be described in detail based on examples. However, the present invention is not limited to the following examples. In addition, unless otherwise indicated, in the following, “part” means “part by mass”.

Example 1
<Preparation of transparent conductive film forming composition A>
First, a mixture having the following composition was subjected to dispersion treatment using zirconia beads having a diameter of 0.1 mm as a dispersion medium and a paint conditioner as a disperser to prepare a dispersion solution.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and after stirring for 30 minutes, “transparent conductive” was passed through a filter (glass fiber filter “AP-25” manufactured by Nippon Millipore). A composition A ”for forming a functional film was obtained.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent B (cyclohexanone): 71.1 parts

(Example 2)
<Preparation of composition B for forming transparent conductive film>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and “transparent conductive film forming composition B” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent A (methyl ethyl ketone): 10.0 parts (7) Solvent B (cyclohexanone): 61 .1 part

(Example 3)
<Preparation of transparent conductive film forming composition C>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and a “transparent conductive film forming composition C” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent A (toluene: non-ketone solvent): 11.1 parts (7) Solvent B (Cyclohexanone): 60.0 parts

Example 4
<Preparation of composition D for forming transparent conductive film>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and “transparent conductive film forming composition D” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent B (cyclohexanone): 40 parts (7) Solvent B (propylene glycol monomethyl ether: non Ketone solvent): 31.1 parts

(Example 5)
<Preparation of transparent conductive film forming composition E>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 6 parts (4) Solvent B (cyclohexanone): 44 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and a “transparent conductive film forming composition E” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent B (cyclohexanone): 67.1 parts

(Example 6)
<Preparation of transparent conductive film forming composition F>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and “transparent conductive film forming composition F” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent A (methyl ethyl ketone): 23.0 parts (7) Solvent B (cyclohexanone): 48 .1 part

(Example 7)
<Preparation of transparent conductive film forming composition G>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and a “transparent conductive film forming composition G” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent A (methyl ethyl ketone): 39.0 parts (7) Solvent B (cyclohexanone): 110 .0 part

(Example 8)
<Preparation of transparent conductive film forming composition H>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle diameter: 20 nm, tin oxide content: 8% by mass) 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts ( 3) Solvent A (methyl isobutyl ketone): 20 parts (4) Solvent B (cyclohexanone): 30 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and “transparent conductive film forming composition H” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent B (cyclohexanone): 4.0 parts

(Comparative Example 1)
<Preparation of composition I for forming transparent conductive film>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl ethyl ketone): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and “transparent conductive film forming composition I” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent A (methyl isobutyl ketone): 51.1 parts (7) Solvent B (cyclohexanone) : 20.0 parts

(Comparative Example 2)
<Preparation of composition J for forming transparent conductive film>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and “transparent conductive film forming composition J” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent A (methyl isobutyl ketone): 61.1 parts (7) Solvent B (cyclohexanone) : 10.0 parts

(Comparative Example 3)
<Preparation of composition K for forming transparent conductive film>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 5 parts (4) Solvent B (cyclohexanone): 45 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and “transparent conductive film forming composition K” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent B (cyclohexanone): 71.1 parts

(Comparative Example 4)
<Preparation of transparent conductive film forming composition L>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 25 parts (4) Solvent B (propylene glycol monomethyl ether acetate: non-ketone solvent): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and a “transparent conductive film forming composition L” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent B (propylene glycol monomethyl ether acetate: non-ketone solvent): 71.1 parts

(Comparative Example 5)
<Preparation of transparent conductive film forming composition M>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 15 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 90 parts of the dispersion solution obtained above, and “transparent conductive film forming composition M” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent B (cyclohexanone): 2.5 parts

(Comparative Example 6)
<Preparation of composition N for forming transparent conductive film>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and “transparent conductive film forming composition N” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent A (methyl isobutyl ketone): 71.1 parts (7) Solvent B (cyclohexanone) 173 parts

(Comparative Example 7)
<Preparation of transparent conductive film forming composition O>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (ethyl acetate: non-ketone solvent): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and “transparent conductive film forming composition O” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent B (cyclohexanone): 71.1 parts

<Preparation of transparent conductive substrate>
Using the transparent conductive film forming compositions A to H of Examples 1 to 8 and the transparent conductive film forming compositions I to O of Comparative Examples 1 to 7, the transparent conductive film was formed as follows. A substrate was produced.

  Using a spin coater, the transparent conductive film forming compositions A to O were dried on a rectangular transparent glass substrate (Corning non-alkali glass “Eagle XG”, thickness: 0.7 mm). Coating was carried out by adjusting the rotation speed so that the film thickness became 0.7 μm, dried for 1 minute in an environment of 25 ° C. after coating, and then dried for 3 minutes in a thermostatic chamber at 80 ° C., Examples 1 to 8 And the transparent conductive substrate of Comparative Examples 1-7 was obtained. At this time, the distance from the composition discharge port of the spin coater to the transparent glass substrate was 5.0 mm.

  Further, the transparent conductive film-forming compositions A to O are dried on a rectangular transparent glass substrate (a non-alkali glass “Eagle XG” manufactured by Corning, thickness: 0.7 mm) using a bar coater. After coating, the count of the bar coater was adjusted so that the film thickness was 0.7 μm. After coating, the coating was dried for 1 minute in an environment of 25 ° C. and then dried for 3 minutes in a thermostatic chamber at 80 ° C. The transparent conductive substrate of Example 8 and Comparative Examples 1 to 7 was obtained.

  Subsequently, the following characteristics were evaluated using the transparent conductive substrate.

<Initial surface electrical resistance value>
For the measurement sample, a transparent conductive substrate having a transparent conductive film on a transparent glass substrate formed by applying and drying a transparent glass substrate within 24 hours after preparing the composition for forming a transparent conductive film is used. It was. The initial surface electrical resistance value of the transparent conductive film was measured using a resistivity meter ("Loresta MCP-T610" manufactured by Mitsubishi Chemical Analytech Co., Ltd.). Specifically, the average value of the surface electrical resistance values at four locations between the central point of each side of the transparent conductive film and the central point of the transparent conductive film was used as the measured value of the initial surface electrical resistance value. . When the initial surface electrical resistance value is less than 10,000 Ω / square, it is evaluated as “good”, when it is 10,000-15,000 Ω / square, “good”, and when it exceeds 15,000 Ω / square, it is evaluated as “bad”. It was.

<Surface roughness>
For the measurement sample, a transparent conductive substrate having a transparent conductive film on a transparent glass substrate formed by applying and drying a transparent glass substrate within 24 hours after preparing the composition for forming a transparent conductive film is used. It was. The surface roughness of the transparent conductive film was evaluated by measuring the arithmetic average roughness (Ra) when observed at a magnification of 100 times using a three-dimensional surface structure analysis microscope (“NewView 5030” manufactured by ZYGO). Ra was less than 5.0 nm as “good”, 5.0 to 8.0 nm as “good”, and 8.0 nm as “bad”. The lower the value of Ra, the better the surface smoothness.

<Haze value>
For the measurement sample, a transparent conductive substrate having a transparent conductive film on a transparent glass substrate formed by applying and drying a transparent glass substrate within 24 hours after preparing the composition for forming a transparent conductive film is used. It was. The haze value is measured using a haze meter (“NDH2000” manufactured by Nippon Denshoku Co., Ltd.) in accordance with a method (mode: Hohou 1) in accordance with JIS K7361, including the transparent glass substrate. Evaluated. The case where the haze value was less than 1.0% was evaluated as “good”, the case where the haze value was 1.0 to 2.0% was evaluated as “good”, and the case where it exceeded 2.0% was evaluated as “bad”. The lower the haze value, the better the optical properties.

<Storage stability of composition>
Storage stability as described below using the transparent conductive film forming compositions A to H of Examples 1 to 8 and the transparent conductive film forming compositions I to O of Comparative Examples 1 to 7 Evaluated.

  After preparing a transparent conductive film forming composition, the measurement sample was stored in an environment at 25 ° C. for 7 days, and then a rectangular transparent glass substrate (a non-alkali glass “Eagle XG” manufactured by Corning Inc., thickness: 0.7 mm) was applied with a spin coater and dried to use a transparent conductive substrate having a transparent conductive film having a thickness of 0.7 μm on the transparent glass substrate.

Surface electrical resistance at 4 points between the center point of each side of the transparent conductive film and the center point of the transparent conductive film using a resistivity meter ("Loresta MCP-T610" manufactured by Mitsubishi Chemical Analytech Co., Ltd.) The value was measured. The average value of the surface electrical resistance values at the four locations was taken as the measured value of the surface electrical resistance value after storage. Storage stability of the composition for forming a transparent conductive film when the change rate calculated using the following formula from the surface electrical resistance value after storage and the initial surface electrical resistance value measured previously is 5% or less Is “good”, the storage stability is “good” when it is 6% or more and less than 10%, and the storage stability is “bad” when it is 10% or more.
Rate of change (%) = [(surface electrical resistance value after storage−initial surface electrical resistance value) / initial surface electrical resistance value] × 100

  The compositions of the transparent conductive film forming compositions A to O produced in Examples 1 to 8 and Comparative Examples 1 to 7 are shown in Tables 1 to 4. Moreover, each said evaluation result is shown in Tables 5-8.

  In Examples 1, 2, and 5-8 using the transparent conductive film forming compositions A to B and E to H, the change rate of the surface electrical resistance value before and after the coating was stored for 7 days in a 25 ° C. environment However, it was 5% or less with respect to the initial surface electric resistance value, and the evaluation of “good” was obtained. In addition, the transparent conductive substrate formed using the transparent conductive film forming compositions A to B and E to H, even when formed with a spin coater or a bar coater, the initial surface electrical resistance value, the surface roughness, Evaluation of “good” was obtained for all items of haze value.

  In Example 3 using the composition C for forming a transparent conductive film, since the ketone solvent in the solvent A is small, the change rate of the surface electric resistance value is 8%, and the storage stability of the composition is “good”. It became evaluation of. In addition, both the transparent conductive substrate formed with a transparent conductive film using a spin coater and the transparent conductive substrate formed with a transparent conductive film using a bar coater have initial surface electrical resistance values of 11,000 Ω / square, It was 200Ω / square, which was evaluated as “good”.

  In Example 4 using the composition D for forming a transparent conductive film, since the ketone solvent in the solvent B is small, the change rate of the surface electric resistance value is 6%, and the storage stability of the composition is “good”. It became evaluation of. Moreover, the initial surface electrical resistance values are 12,000 Ω / square and 11,800 Ω / square, respectively, for the transparent conductive substrate on which the transparent conductive film is formed by either the spin coater or the bar coater. It became. Further, the haze values of the transparent conductive substrate were 1.2% and 1.2%, respectively, and the evaluation was “good”.

  On the other hand, in Comparative Example 1 using the transparent conductive film forming composition I, the transparent conductive substrate on which the transparent conductive film is formed using a spin coater has a large amount of the solvent A having a relative evaporation rate of 1 or more. The solvent was quickly dried from the composition, and the initial surface electrical resistance value and the haze value were 13,500 Ω / square and 1.2%, respectively, which were evaluated as “good”. Moreover, the surface roughness was evaluated as “bad” at 8.5 nm.

  In Comparative Example 2 using the composition J for forming a transparent conductive film, the transparent conductive substrate on which the transparent conductive film was formed using a spin coater had a solvent A having a relative evaporation rate of 1 or more as compared with Comparative Example 1. In many cases, the drying of the solvent from the composition is faster than that of Comparative Example 1, so that the initial surface electrical resistance value is evaluated as “bad” at 15,500Ω / square, and the surface roughness is also evaluated as “bad” at 9.6 nm. The haze value was 2.3%, which was evaluated as “bad”.

  In Comparative Example 3 using the composition K for forming a transparent conductive film, since the amount of the solvent B having a relative evaporation rate of 1 or less is too much, the change rate of the surface electrical resistance value is 7%, and the storage stability of the composition is improved. It was evaluated as “good”. In addition, the transparent conductive substrate on which the transparent conductive film was formed by any of the spin coater and bar coater coating methods was evaluated as “bad” with initial surface electrical resistance values of 17,200 Ω / square and 17,500 Ω / square, respectively. The surface roughness was evaluated as “good” at 7.3 nm and 7.8 nm, respectively, and the haze values were evaluated as “good” at 1.7% and 1.8%, respectively.

  In Comparative Example 4 using the composition L for forming a transparent conductive film, since the ketone solvent in the solvent B is 0, the change rate of the surface electrical resistance value is 20%, and the storage stability of the composition is “ It was evaluated as “bad”. In addition, the transparent conductive substrate on which the transparent conductive film is formed by any coating method of spin coater or bar coater has an initial electric resistance value of 23,000 Ω / square, 22,500 Ω / square, and a surface roughness of 11.5 nm, respectively. 11.0 nm and haze values were 2.8% and 2.6%, respectively, and all were evaluated as “bad”.

  In Comparative Example 5 using the composition M for forming a transparent conductive film, the solid content concentration of the composition was high, so that the viscosity increased and sufficient dispersion could not be obtained, and the rate of change in the surface electrical resistance value was 8%. The storage stability of the product was evaluated as “good”. In addition, the transparent conductive substrate on which the transparent conductive film is formed by any coating method of spin coater or bar coater has an initial electric resistance value of 16,200 Ω / square, 16,300 Ω / square, and a surface roughness of 8.8 nm, respectively. 8.4 nm and haze values were 2.3% and 2.1%, respectively, which were evaluated as “bad”, respectively.

  In Comparative Example 6 using the composition N for forming a transparent conductive film, the transparent conductive substrate on which the transparent conductive film was formed using a spin coater had a low solid content concentration, so that the drying time was reduced when forming the coating film. The initial surface electrical resistance value and haze value were 15,200 Ω / square and 2.3%, respectively, which were evaluated as “bad”. Further, the surface roughness was 7.1 nm, and the evaluation was “good”. Further, the haze value of the transparent conductive substrate on which the transparent conductive film was formed by the bar coater coating method was 1.5%, which was evaluated as “good”.

  In Comparative Example 7 using the transparent conductive film-forming composition O, since the ketone solvent in the solvent A is 0, the change rate of the surface electrical resistivity is 12%, and the storage stability of the composition is “ It was evaluated as “bad”. In addition, the transparent conductive substrate on which the transparent conductive film is formed by any of the spin coater and bar coater coating methods has an initial electric resistance value of 21,000 Ω / square, 21,200 Ω / square, and a surface roughness of 8.8 nm, respectively. , 8.2 nm, and haze values were 2.1% and 2.1%, respectively.

  The present invention can be implemented in other forms than the above without departing from the spirit of the present invention. The embodiments disclosed in the present application are merely examples, and the present invention is not limited thereto. The scope of the present invention is construed in preference to the description of the appended claims rather than the description of the above specification, and all modifications within the scope equivalent to the claims are construed in the scope of the claims. It is included.

  The present invention relates to a composition for forming a transparent conductive film and a transparent conductive substrate formed using this composition.

  Conventionally, a transparent conductive film has been manufactured by depositing a transparent conductive metal oxide such as tin-containing indium oxide on a substrate by a so-called dry process such as sputtering or vapor deposition. Since the production of the transparent conductive film using such a dry process method is performed under vacuum conditions, an expensive production apparatus is required, the production efficiency is low, and it is not suitable for mass production. Therefore, as a method for replacing the dry process method, a wet process in which a dispersion composition containing transparent conductive particles is applied to form a transparent conductive film is being studied.

  Among transparent conductive particles, tin-containing indium oxide (ITO) particles in which tin is contained in indium oxide are CRTs that are required to be prevented from static electricity and electromagnetic waves because of their high translucency for visible light and high conductivity. It has been used as a suitable material for screens, LCD screens and the like.

  In addition to the tin-containing indium oxide that has been used in the transparent conductive film dry process method, the dispersion composition contains transparent conductive particles such as tin oxide, antimony-containing tin oxide, zinc oxide, and fluorine-containing tin oxide. A coating-type transparent conductive film formed by coating on a material has also been put into practical use.

  As a solvent used for the coating type transparent conductive film, Patent Document 1 proposes hydrocarbons, aromatics, ketones, alcohols, glycols, glycol esters, glycol ethers and the like. Moreover, as a manufacturing method of the coating type transparent conductive sheet provided with the coating type transparent conductive film, Patent Document 1 specifies the amount of residual solvent in the dry coating film as a ratio to the dry film thickness, and the surface electrical resistance value. A coating type transparent conductive sheet having a small change rate and a low haze and a method for producing the same have been proposed.

  In Patent Document 2, the solvent used for the coating type transparent conductive film is limited to at least one selected from ketones and esters, and the relative evaporation rate is 1 when the evaporation rate of butyl acetate is 1 as the solvent. The above-mentioned solvent A and the solvent B having a relative evaporation rate of less than 1 are solvent A: solvent B = 95: 5 to 70:30 in a weight ratio, and the initial surface electrical resistance is satisfied by satisfying limited drying conditions. A composition for a transparent conductive sheet having a low value and excellent in transparency capable of suppressing an increase in the surface electric resistance value over time, and a method for producing a transparent conductive sheet using the composition have been proposed. .

JP 2012-190713 A JP, 2006-207607, A

  However, in general, in a coating composition containing transparent conductive particles, a binder resin, and a solvent, the stability of the composition is insufficient in the solvent system (MEK / toluene) described in the examples of Patent Document 1, Long-term storage may increase the viscosity of the coating composition. Further, when a transparent conductive sheet is formed using such a composition, there is a problem that the stability of the surface electric resistance value is insufficient and the surface electric resistance value increases with time.

  Moreover, the composition for transparent conductive sheets manufactured by said solvent composition described in patent document 2 is based on the composition of predetermined | prescribed solid content concentration by coating systems, such as a gravure coater, a bar coater, and a die coater. In the method of applying full-scale drying after applying the film with shearing force and leveling the coating sufficiently in the initial stage of the constant rate drying period from the material preheating period in which rapid solvent evaporation does not occur, Although the above-described effects can be obtained, as in the spray coater coating method, in the method of spraying a composition having a predetermined solid content concentration in a mist form and applying it without applying a shearing force to the substrate, at the spraying stage, Rapid evaporation of the solvent occurs, surface roughness and haze increase due to leveling failure due to increase in solid content concentration, or poor filling of conductive particles due to short time to dry solidification Thus surface resistivity there is a risk or to increase. In addition, as in the spin coater coating method, a method in which a droplet of a composition having a predetermined solid content concentration is dropped on a substrate that rotates at high speed and is applied by applying a shearing force in the horizontal direction by centrifugal force. Rapid rotation of the solvent occurs due to high-speed rotation, and the surface roughness and haze value increase due to poor spread of the composition and poor leveling due to an increase in solid content concentration, and the time until solidification by drying is short. There was a risk that the surface electrical resistance value would increase due to poor filling of the conductive particles.

  As described above, the coating composition according to the prior art uses a coating method in which the storage stability of the composition and the stability of the surface electrical resistance value are still insufficient, and it is difficult to sufficiently level the composition. In some cases, the transparent conductive film may not have sufficiently satisfactory characteristics in terms of surface roughness, haze value, and surface electrical resistance value.

  The present invention is excellent in storage stability, can reduce the surface roughness and haze value of the transparent conductive film formed on the transparent substrate, and can sufficiently reduce the surface electric resistance value, regardless of the coating method. Provided is a composition for forming a transparent conductive film.

  The composition for forming a transparent conductive film of the present invention is a composition for forming a transparent conductive film comprising transparent conductive particles, a binder resin, and a solvent. The solid content concentration is 20 to 50% by mass, and the solvent includes a solvent A having a relative evaporation rate of 1 or more and a solvent B having a relative evaporation rate of less than 1 when the evaporation rate of butyl acetate is 1. The mass ratio of the solvent A and the solvent B is solvent A: solvent B = 40: 60 to 5:95, and both the solvent A and the solvent B include at least a ketone solvent. It is characterized by including.

  The transparent conductive substrate of the present invention is a transparent conductive substrate including a transparent substrate and a transparent conductive film disposed on the transparent substrate, and the transparent conductive film of the present invention is It was formed using the composition for transparent conductive film formation.

  According to the present invention, the storage stability is excellent, the surface roughness and haze value of the transparent conductive film formed on the transparent substrate are small, and the surface electrical resistance value is sufficiently low regardless of the coating method. A possible composition for forming a transparent conductive film and a transparent conductive substrate formed using the composition can be provided.

  In the present invention, a film immediately after a transparent conductive film forming composition containing transparent conductive particles, a binder resin and a solvent is applied on a transparent substrate is used as the transparent conductive coating film, and the solvent of the transparent conductive coating film is used. The evaporated and dried film is referred to as a transparent conductive film, and the film including the transparent substrate and the transparent conductive film is referred to as a transparent conductive substrate. Moreover, the composition for forming a transparent conductive film may be simply referred to as a composition.

<Transparent conductive film forming composition>
The composition for forming a transparent conductive film is obtained by preparing transparent conductive particles and a binder resin by dispersing them in a solvent. The solid content concentration of the composition for forming a transparent conductive film is in the range of 20 to 50% by mass. The solid content concentration is preferably 25 to 45 mass%, more preferably 30 to 40 mass%.

  When the solid content concentration of the composition for forming a transparent conductive film is less than 20% by mass, the amount of solvent in the composition for forming a transparent conductive film increases, and therefore, it is relatively easy to evaporate as described later. Solvent A (solvent having a relative evaporation rate of 1 or more when the evaporation rate of butyl acetate is 1) and solvent B (relative evaporation rate of 1 when the evaporation rate of butyl acetate is 1) are relatively difficult to evaporate. Less solvent), the amount of solvent to be evaporated and dried from the transparent conductive coating film is large. Therefore, the convection of the composition accompanying the evaporation of the solvent reduces the filling property of the transparent conductive particles, and the transparent conductive property Since the contact between the particles decreases, the surface electrical resistance value may not be sufficiently lowered. In addition, the surface roughness may increase, or the amount of residual solvent in the transparent conductive film may increase.

  When the solid content concentration exceeds 50 mass%, the amount of the solvent is small, so that the dispersion of the composition for forming a transparent conductive film becomes insufficient, and the dispersion stability is lowered, so that the storage stability of the composition is lowered. Moreover, there is a risk of causing leveling defects.

  In the composition for forming a transparent conductive film having a solid content concentration of 20 to 50% by mass, in other words, in the composition for forming a transparent conductive film of the present invention containing 50 to 80% by mass of the solvent, the solvent has an evaporation rate. By using a solvent in which different solvents A and B are mixed, the solvent A is relatively easily evaporated when the transparent conductive film-forming composition is applied to a transparent substrate and dried to form a transparent conductive film. Thus, the amount of residual solvent in the transparent conductive film can be reduced. In addition, the solvent B, which is relatively hard to evaporate, gradually evaporates as compared to the solvent A, which is easy to evaporate. As a result, uniform deposition and filling of the transparent conductive particles are sufficient until the transparent conductive coating film is dried and solidified. Therefore, the filling property is improved, and the contact between the transparent conductive particles is increased, whereby the surface electrical resistance value of the transparent conductive film can be sufficiently reduced.

  When mixing the solvent A, which is relatively easy to evaporate, and the solvent B, which is relatively difficult to evaporate, the mass ratio of the solvent A and the solvent B is as follows: solvent A: solvent B = 40: 60-5 : 95 range. By setting it in the above range, the solid content concentration of the composition is likely to increase as in the spray coater coating method and the spin coater coating method, and the evaporation rate of the solvent is moderated even in a coating method in which the time to dry solidification is short. It is possible to suppress a rapid increase in the solid content concentration as compared with the prior art composition, and it is possible to ensure a long time to dry solidification. As a result, the leveling property and spreadability of the composition are improved, the surface roughness and haze value of the transparent conductive film can be reduced, and the uniform deposition and filling of the transparent conductive particles proceeds sufficiently, that is, Fillability is improved and a transparent conductive film having a low surface electric resistance value can be realized. In addition, the amount of residual solvent in the transparent conductive film can be made equal to or less than that of the prior art composition.

  If the proportion of the solvent A, which is relatively easy to evaporate in the entire mixed solvent, is less than 5 parts, the wettability of the solvent with respect to the conductive particles may be reduced, and it may be difficult to maintain dispersion stability. . Moreover, the drying property of the transparent conductive coating film immediately after coating becomes extremely slow, and there is a possibility that the amount of residual solvent in the transparent conductive coating film increases. Further, when the proportion of the solvent A that is relatively easy to evaporate in the entire mixed solvent exceeds 40 parts, the amount of the solvent A that is relatively easy to evaporate is too much, so that the spray coater coating method and the spin coater coating method are used. In a coating method in which the solid content concentration of the composition is likely to increase and the time until drying and solidification is short, the surface roughness and haze value increase due to poor spread of the composition and poor leveling due to the increase in solid content concentration, There is a possibility that the surface electrical resistance value may increase due to poor filling of the conductive particles due to the short time until drying and solidification. The ratio of the solvent A in the entire mixed solvent is preferably in the range of 10 to 30 parts.

  Both the solvent A and the solvent B include at least a ketone solvent. Here, the content of the ketone solvent in the solvent A is preferably 90% by mass or more based on the total amount of the solvent A. By setting it as the said range, the dispersibility of a composition can improve and it can be set as the composition for transparent conductive film formation excellent in storage stability. When the content of the ketone solvent in the solvent A is less than 90% by mass with respect to the total amount of the solvent A, the dispersibility of the composition is lowered, and the storage stability of the composition may be lowered. The content of the ketone solvent in the solvent A is more preferably 95% by mass or more based on the total amount of the solvent A.

  The content of the ketone solvent in the solvent B is preferably 70% by mass or more with respect to the total amount of the solvent B. By setting the above range, the dispersibility of the composition is improved, the evaporation rate of the solvent at the time of application is moderated, and the rapid increase in the solid content concentration can be suppressed, so that the leveling property and spreadability of the composition are improved. And the surface roughness and haze value of the transparent conductive substrate can be reduced. In addition, since the time until drying and solidification can be secured for a long time, uniform deposition and filling of transparent conductive particles sufficiently proceeds, that is, the filling property is improved, and a transparent conductive substrate having a low surface electric resistance value is obtained. be able to. When the content of the ketone solvent in the solvent B is less than 70% by mass with respect to the total amount of the solvent B, the dispersibility of the composition is lowered, and the storage stability of the composition may be lowered. The content of the ketone solvent in the solvent B is more preferably 80% by mass or more with respect to the total amount of the solvent B.

  The content of the ketone solvent in the solvent A is 90% by mass or more with respect to the total amount of the solvent A, and the content of the ketone solvent in the solvent B is 70% by mass or more with respect to the total amount of the solvent B. Then, the solvent A and the solvent B may contain a solvent other than the ketone solvent.

(solvent)
As the solvent, a solvent A having a relative evaporation rate of 1 or more when the evaporation rate of butyl acetate is 1, and a solvent B having a relative evaporation rate of less than 1 are used. Here, the relative evaporation rate is a relative evaporation rate when the evaporation rate of butyl acetate is 1, and it means that the larger the value, the easier the evaporation, and the smaller the value, the harder the evaporation.

  Both of the solvent A and the solvent B include at least a ketone solvent.

  As the ketone solvent classified into the solvent A having a relative evaporation rate of 1 or more, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK) and the like can be used. Examples of the ketone solvent classified as the solvent B having a relative evaporation rate of less than 1 include cyclopentanone, cyclohexanone, cycloheptanone, diisobutyl ketone (DIBK), 2-heptanone, methyl isoamyl ketone, and methyl-n. -Propyl ketone, isophorone, etc. can be used.

  As long as the relative evaporation rate when the evaporation rate of butyl acetate in the solvent A is 1 or more and the relative evaporation rate when the evaporation rate of butyl acetate is 1 in the solvent B is less than 1, the above The solvent A and the solvent B may be mixed with alcohol-based, ester-based, aliphatic-based, aromatic-based, glycol-based, ether-based, or glycol-ether-based solvents in addition to the above-mentioned ketone-based solvents. When these solvents are used by mixing with a ketone solvent, it is desirable to add them to such an extent that the dispersibility of the conductive fine particles is not impaired.

  Examples of the solvent classified as the solvent A other than the ketone solvents include methyl alcohol, ethyl alcohol, isopropyl alcohol, ethyl acetate, isopropyl acetate, normal propyl acetate, tetrahydrofuran, hexane, heptane, cyclohexane, and toluene. In addition to the above-mentioned ketone solvents, the solvents classified as solvent B include normal propanol, normal butanol, ethyl lactate, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether acetate, ethylene glycol mono Examples include butyl ether, diethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, 1,4-dioxane, xylene and the like.

(Transparent conductive particles)
The transparent conductive particles are not particularly limited as long as the particles have both transparency and conductivity. For example, conductive metal oxide particles and conductive nitride particles can be used. Examples of the conductive metal oxide particles include metal oxide particles such as indium oxide, tin oxide, zinc oxide, and cadmium oxide. Also, conductive metal oxide particles doped with tin, antimony, aluminum, gallium, with one or more metal oxides selected from the group consisting of indium oxide, tin oxide, zinc oxide and cadmium oxide as main components, For example, tin-containing indium oxide (ITO) particles, antimony-containing tin oxide (ATO) particles, aluminum-containing zinc oxide (AZO) particles, gallium-containing zinc oxide (GZO) particles, and conductive metal oxide particles obtained by replacing ITO with aluminum. Can be used. Among these, ITO particles are particularly preferable from the viewpoint of excellent transparency and conductivity. In addition, from the viewpoint of conductivity, in the ITO particles, the amount of tin added to the entire ITO is preferably in the range of 1 to 20% by mass in terms of tin oxide. The conductivity is improved by adding tin to ITO. However, when the amount of tin added is less than 1% by mass, the improvement in conductivity tends to be poor. Tend to be less.

  The transparent conductive particles preferably have an average primary particle diameter in the range of 10 to 200 nm. When the average primary particle diameter is less than 10 nm, it is considered that the dispersion treatment becomes difficult and the particles are easily aggregated, but the haze increases and the optical properties tend to be inferior. In addition, when the average primary particle diameter exceeds 200 nm, it seems to be due to the scattering of visible light by the particles, but the haze tends to increase. Here, the average primary particle diameter is, for example, at least 100 particles after observing and measuring the particle diameter of each particle using an electron microscope on the surface or cross section of the transparent conductive film formed on the transparent substrate. The average particle diameter is the average of the particle diameters.

(Binder resin)
It is preferable that content of the said binder resin contained in the said composition for transparent conductive film formation is the range of 5-18 mass parts with respect to 100 mass parts of transparent conductive particles. When the content of the binder resin is less than 5 parts by mass, the effect of improving the coating film strength tends to be poor, and when the content of the binder resin exceeds 18 parts by mass, the surface electrical resistance value tends to increase. There is a possibility that good conductivity cannot be obtained.

  Although it does not specifically limit as said binder resin, Resin whose glass transition temperature is the range of 30-120 degreeC is preferable. By using a resin having a glass transition temperature in the range of 30 to 120 ° C. as the binder resin, the transparent conductive film can have appropriate flexibility. As the binder resin, for example, a thermoplastic resin having a glass transition temperature of 30 to 120 ° C. or a radiation curable resin having a glass transition temperature of 30 to 120 ° C. can be used. The said binder resin may be used independently or may be used in combination of 2 or more type. Here, the measurement of the glass transition temperature can be performed in accordance with Japanese Industrial Standard (JIS) K7121 using a DSC method based on so-called thermal analysis.

  As a thermoplastic resin whose said glass transition temperature is the range of 30-120 degreeC, an acrylic resin or a polyester resin etc. can be used, for example.

  Examples of the acrylic resin include “Dianar BR-60”, “Dianar BR-64”, “Dianar BR-75”, “Dianar BR-77”, “Dianar BR” manufactured by Mitsubishi Rayon Co., Ltd. −80 ”,“ Dianar BR-83 ”,“ Dianar BR-87 ”,“ Dianar BR-90 ”,“ Dianar BR-95 ”,“ Dianar BR-96 ”,“ Dianar BR-100 ” ”,“ Dianar BR-101 ”,“ Dianar BR-105 ”,“ Dianar BR-106 ”,“ Dianar BR-107 ”,“ Dianar BR-108 ”,“ Dianar BR-110 ”, “Dianar BR-113”, “Dianar BR-122”, “Dianar BR-605”, “Dianar MB-2539”, “Dianar MB-2389”, “Dianar MB-2487”, “Dianar MB-2660”, “Dianar MB-2952”, “Dianar MB-3015”, “Dianar MB-7033”, etc. .

  Examples of the polyester resin include “Byron 200”, “Byron 220”, “Byron 226”, “Byron 240”, “Byron 245”, “Byron 270”, “Byron 280”, “Byron” manufactured by Toyobo Co., Ltd. 290 ”,“ Byron 296 ”,“ Byron 660 ”,“ Byron 885 ”,“ Byron GK110 ”,“ Byron GK250 ”,“ Byron GK360 ”,“ Byron GK640 ”,“ Byron GK880 ”and the like.

Although it does not specifically limit as said radiation curable resin whose said glass transition temperature is the range of 30-120 degreeC, For example, an acrylate monomer, a methacrylate monomer, an epoxy acrylate, a urethane acrylate, a polyester acrylate, an acrylic oligomer etc. are mentioned. Specifically, isobornyl acrylate, 2-phenoxyethyl methacrylate, tripropylene glycol diacrylate, diethylene glycol diacrylate, ethoxylated bisphenol A dimethacrylate, trimethylolpropane triacrylate, dipentaerythritol pentaacrylate, etc. may be used. it can. Here, the glass transition temperature of the radiation curable resin is, for example, an ultraviolet polymerization initiator such as 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1 with respect to 100 parts by mass of the resin. -It is preferable to use the measurement value after the radiation curing treatment obtained by adding 5 parts by mass of ON and irradiating with ultraviolet rays at 500 mJ / cm ² .

When a radiation curable resin is used as the binder resin, the curing treatment may be performed by radiation such as ultraviolet rays, electron beams, and β rays. Among these, it is convenient to use ultraviolet rays. In this case, an ultraviolet polymerization initiator may be further added to the radiation curable resin. As the ultraviolet polymerization initiator, the following can be used. For example, benzoin isopropyl ether, benzophenone, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone, 2,4-diethylthioxanthone, methyl o-benzoylbenzoate, 4,4-bisdiethylaminobenzophenone, 2, 2-diethoxyacetophenone Bruno emissions, benzyl, 2-chloro thioxanthone, diisopropyl thio Giang Son, 9,10-anthraquinone, Bensoin, benzoin methyl ether, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2 -Methyl-propiophenone, 4-isopropyl-2-hydroxy-2-methylpropiophenone, α, α-dimethoxy-α-phenylacetone and the like can be used. The said ultraviolet polymerization initiator may be used independently and may be used in combination of 2 or more type.

  The ultraviolet polymerization initiator is preferably added in an amount of 1 to 20 parts by mass with respect to 100 parts by mass of the radiation curable resin. When the addition amount of the ultraviolet polymerization initiator is less than 1 part by mass, it is considered that the curability of the resin is inferior, but the strength of the transparent conductive film tends to be inferior. Moreover, when the addition amount of the said ultraviolet polymerization initiator exceeds 20 mass parts, although it seems that bridge | crosslinking does not fully advance, it exists in the tendency for the intensity | strength of a transparent conductive film to be inferior.

  Moreover, you may use thermosetting resins, such as an epoxy resin, as resin whose glass transition temperature is the range of 30-120 degreeC.

(Other additives)
The composition for forming a transparent conductive film may contain a dispersant, a plasticizer, an antistatic agent and the like in addition to the transparent conductive particles and the binder resin.

  As the dispersant, a dispersant containing at least an anionic functional group is preferably used, and a polyester resin containing an anionic functional group and an acrylic resin containing an anionic functional group are more preferably used. For example, carboxylic acid-containing acrylic resins, acid-containing polyester resins, acid and base-containing polyester resins, and the like can be used. Specifically, “Dianar MR-2539”, “Dianar MB-2389”, “Dianar MB-2660”, “Dianar MB-3015”, “Dianar BR-84” manufactured by Mitsubishi Rayon Co., Ltd., etc. Or “Solspurs 3000”, “Solspurs 21000”, “Solspurs 32000”, “Solspurs 36000”, “Solspurs 41000”, “Solspurs 43000”, “Solspurs 44000”, “Solspurs 45000” manufactured by Abyssia A commercially available product such as “Solspers 56000” can be used.

  The preparation method of the said composition for transparent conductive film formation should just disperse | distribute transparent conductive particle and binder resin in a solvent, and the dispersion | distribution method is not specifically limited, respectively. For example, a dispersion process using a bead mill such as a sand grind mill, an ultrasonic disperser, a three roll mill, or the like can be mentioned, but a dispersion process using a bead mill is preferable from the viewpoint of better dispersibility.

<Transparent conductive substrate>
The transparent conductive substrate includes a transparent substrate and a transparent conductive film disposed on the transparent substrate, and the transparent conductive film is formed using the above-described composition for forming a transparent conductive film. ing. The total light transmittance of the transparent conductive substrate is preferably 75% or more, and more preferably 85% or more. Further, the haze value is preferably 2% or less, and more preferably 1% or less. By setting the total light transmittance and haze value of the transparent conductive substrate to the above ranges, the transparent conductive substrate can be selected from, for example, a touch panel, a light control film electrode, a transparent surface heating element, a display antistatic film, It can be suitably used for a transparent conductive substrate for an electromagnetic shielding material.

(Transparent substrate)
The transparent substrate is not particularly limited as long as it is made of a transparent material having translucency. For example, polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyolefins; cellulose resins such as cellulose triacetate; amide resins such as nylon and aramid; polyether resins such as polyphenylene ether and polysulfone ether; polycarbonate resins; A film or a substrate made of a material such as polyamide resin; polyimide resin; polyamideimide resin; aromatic polyamide resin; can be used. The transparent substrate may be formed using glass, ceramics, or the like. In that case, inorganic glass or organic glass (polymer substrate) can be used as the glass material. In the case of a film or substrate, the thickness of the transparent substrate is preferably in the range of 3 to 300 μm, and more preferably in the range of 25 to 200 μm. When the transparent conductive film forming composition is applied using a spray method, a spin method or the like, the transparent substrate is preferably formed of glass, ceramics, or the like.

  In the present invention, the term “transparent” means that the total light transmittance measured in accordance with JIS K7161: 1997 is 75% or more.

  Additives such as an antioxidant, a flame retardant, an ultraviolet absorber, a lubricant, and an antistatic agent may be added to the transparent substrate. Furthermore, in order to improve adhesion with the transparent conductive film formed on the transparent substrate, an easy-adhesive layer (for example, a primer layer) is provided on the substrate surface, or surface treatment such as corona treatment or plasma treatment. Can be done.

  The method for forming the transparent conductive substrate by applying the transparent conductive film forming composition to the transparent substrate is not particularly limited as long as it is a coating method capable of forming a smooth coating film. For example, a coating method such as a gravure roll method, a micro gravure roll method, a spray method, a spin method, a knife method, a kiss method, a squeeze method, a reverse roll method, a dip method, or a bar coating method can be used. In particular, the composition of the present invention is preferably used in a coating method in which the solid content concentration of the composition tends to increase and the time until drying and solidification is short, such as a spray coater coating method and a spin coater coating method.

  As a method for drying the coating film, hot air may be applied from the transparent conductive coating film side or from the transparent substrate side. Moreover, you may make a heat source contact the transparent substrate side directly. Moreover, you may dry a transparent conductive coating film by a non-contact method with a heat source using an infrared heater, a far-infrared heater, etc. Furthermore, you may dry naturally in the space where temperature and humidity were controlled.

  Hereinafter, the present invention will be described in detail based on examples. However, the present invention is not limited to the following examples. In addition, unless otherwise indicated, in the following, “part” means “part by mass”.

Example 1
<Preparation of transparent conductive film forming composition A>
First, a mixture having the following composition was subjected to dispersion treatment using zirconia beads having a diameter of 0.1 mm as a dispersion medium and a paint conditioner as a disperser to prepare a dispersion solution.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and after stirring for 30 minutes, “transparent conductive” was passed through a filter (glass fiber filter “AP-25” manufactured by Nippon Millipore). A composition A ”for forming a functional film was obtained.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent B (cyclohexanone): 71.1 parts

(Example 2)
<Preparation of composition B for forming transparent conductive film>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and “transparent conductive film forming composition B” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent A (methyl ethyl ketone): 10.0 parts (7) Solvent B (cyclohexanone): 61 .1 part

(Example 3)
<Preparation of transparent conductive film forming composition C>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and a “transparent conductive film forming composition C” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent A (toluene: non-ketone solvent): 11.1 parts (7) Solvent B (Cyclohexanone): 60.0 parts

Example 4
<Preparation of composition D for forming transparent conductive film>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and “transparent conductive film forming composition D” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent B (cyclohexanone): 40 parts (7) Solvent B (propylene glycol monomethyl ether: non Ketone solvent): 31.1 parts

(Example 5)
<Preparation of transparent conductive film forming composition E>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 6 parts (4) Solvent B (cyclohexanone): 44 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and a “transparent conductive film forming composition E” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent B (cyclohexanone): 67.1 parts

(Example 6)
<Preparation of transparent conductive film forming composition F>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and “transparent conductive film forming composition F” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent A (methyl ethyl ketone): 23.0 parts (7) Solvent B (cyclohexanone): 48 .1 part

(Example 7)
<Preparation of transparent conductive film forming composition G>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and a “transparent conductive film forming composition G” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent A (methyl ethyl ketone): 39.0 parts (7) Solvent B (cyclohexanone): 110 .0 part

(Example 8)
<Preparation of transparent conductive film forming composition H>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 20 parts (4) Solvent B (cyclohexanone): 30 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and “transparent conductive film forming composition H” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent B (cyclohexanone): 4.0 parts

(Comparative Example 1)
<Preparation of composition I for forming transparent conductive film>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl ethyl ketone): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and “transparent conductive film forming composition I” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent A (methyl isobutyl ketone): 51.1 parts (7) Solvent B (cyclohexanone) : 20.0 parts

(Comparative Example 2)
<Preparation of composition J for forming transparent conductive film>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and “transparent conductive film forming composition J” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent A (methyl isobutyl ketone): 61.1 parts (7) Solvent B (cyclohexanone) : 10.0 parts

(Comparative Example 3)
<Preparation of composition K for forming transparent conductive film>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 5 parts (4) Solvent B (cyclohexanone): 45 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and “transparent conductive film forming composition K” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent B (cyclohexanone): 71.1 parts

(Comparative Example 4)
<Preparation of transparent conductive film forming composition L>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 25 parts (4) Solvent B (propylene glycol monomethyl ether acetate: non-ketone solvent): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and a “transparent conductive film forming composition L” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent B (propylene glycol monomethyl ether acetate: non-ketone solvent): 71.1 parts

(Comparative Example 5)
<Preparation of transparent conductive film forming composition M>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 15 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 90 parts of the dispersion solution obtained above, and “transparent conductive film forming composition M” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent B (cyclohexanone): 2.5 parts

(Comparative Example 6)
<Preparation of composition N for forming transparent conductive film>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (methyl isobutyl ketone): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and “transparent conductive film forming composition N” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent A (methyl isobutyl ketone): 71.1 parts (7) Solvent B (cyclohexanone) 173 parts

(Comparative Example 7)
<Preparation of transparent conductive film forming composition O>
First, a dispersion solution was prepared in the same manner as in Example 1 using a mixture having the following composition.
(1) ITO particles (average primary particle size: 20 nm, tin oxide content: 8% by mass): 45 parts (2) Binder resin (acrylic resin, “Dianal BR-113” manufactured by Mitsubishi Rayon Co., Ltd.): 5 parts (3) Solvent A (ethyl acetate: non-ketone solvent): 25 parts (4) Solvent B (cyclohexanone): 25 parts

Next, a mixture of the following components was added to 100 parts of the dispersion solution obtained above, and “transparent conductive film forming composition O” was obtained in the same manner as in Example 1.
(5) Binder resin (acrylic resin, “Dainal BR-83” manufactured by Mitsubishi Rayon Co., Ltd.): 1.9 parts (6) Solvent B (cyclohexanone): 71.1 parts

<Preparation of transparent conductive substrate>
Using the transparent conductive film forming compositions A to H of Examples 1 to 8 and the transparent conductive film forming compositions I to O of Comparative Examples 1 to 7, the transparent conductive film was formed as follows. A substrate was produced.

  Using a spin coater, the transparent conductive film forming compositions A to O were dried on a rectangular transparent glass substrate (Corning non-alkali glass “Eagle XG”, thickness: 0.7 mm). Coating was carried out by adjusting the rotation speed so that the film thickness became 0.7 μm, dried for 1 minute in an environment of 25 ° C. after coating, and then dried for 3 minutes in a thermostatic chamber at 80 ° C., Examples 1 to 8 And the transparent conductive substrate of Comparative Examples 1-7 was obtained. At this time, the distance from the composition discharge port of the spin coater to the transparent glass substrate was 5.0 mm.

  Further, the transparent conductive film-forming compositions A to O are dried on a rectangular transparent glass substrate (a non-alkali glass “Eagle XG” manufactured by Corning, thickness: 0.7 mm) using a bar coater. After coating, the count of the bar coater was adjusted so that the film thickness was 0.7 μm. After coating, the coating was dried for 1 minute in an environment of 25 ° C. and then dried for 3 minutes in a thermostatic chamber at 80 ° C. The transparent conductive substrate of Example 8 and Comparative Examples 1 to 7 was obtained.

  Subsequently, the following characteristics were evaluated using the transparent conductive substrate.

<Initial surface electrical resistance value>
For the measurement sample, a transparent conductive substrate having a transparent conductive film on a transparent glass substrate formed by applying and drying a transparent glass substrate within 24 hours after preparing the composition for forming a transparent conductive film is used. It was. The initial surface electrical resistance value of the transparent conductive film was measured using a resistivity meter ("Loresta MCP-T610" manufactured by Mitsubishi Chemical Analytech Co., Ltd.). Specifically, the average value of the surface electrical resistance values at four locations between the central point of each side of the transparent conductive film and the central point of the transparent conductive film was used as the measured value of the initial surface electrical resistance value. . When the initial surface electrical resistance value is less than 10,000 Ω / square, it is evaluated as “good”, when it is 10,000-15,000 Ω / square, “good”, and when it exceeds 15,000 Ω / square, it is evaluated as “bad”. It was.

<Surface roughness>
For the measurement sample, a transparent conductive substrate having a transparent conductive film on a transparent glass substrate formed by applying and drying a transparent glass substrate within 24 hours after preparing the composition for forming a transparent conductive film is used. It was. The surface roughness of the transparent conductive film was evaluated by measuring the arithmetic average roughness (Ra) when observed at a magnification of 100 times using a three-dimensional surface structure analysis microscope (“NewView 5030” manufactured by ZYGO). Ra was less than 5.0 nm as “good”, 5.0 to 8.0 nm as “good”, and 8.0 nm as “bad”. The lower the value of Ra, the better the surface smoothness.

<Haze value>
For the measurement sample, a transparent conductive substrate having a transparent conductive film on a transparent glass substrate formed by applying and drying a transparent glass substrate within 24 hours after preparing the composition for forming a transparent conductive film is used. It was. The haze value is measured using a haze meter (“NDH2000” manufactured by Nippon Denshoku Co., Ltd.) in accordance with a method (mode: Hohou 1) in accordance with JIS K7361, including the transparent glass substrate. Evaluated. The case where the haze value was less than 1.0% was evaluated as “good”, the case where the haze value was 1.0 to 2.0% was evaluated as “good”, and the case where it exceeded 2.0% was evaluated as “bad”. The lower the haze value, the better the optical properties.

<Storage stability of composition>
Storage stability as described below using the transparent conductive film forming compositions A to H of Examples 1 to 8 and the transparent conductive film forming compositions I to O of Comparative Examples 1 to 7 Evaluated.

  After preparing a transparent conductive film forming composition, the measurement sample was stored in an environment at 25 ° C. for 7 days, and then a rectangular transparent glass substrate (a non-alkali glass “Eagle XG” manufactured by Corning Inc., thickness: 0.7 mm) was applied with a spin coater and dried to use a transparent conductive substrate having a transparent conductive film having a thickness of 0.7 μm on the transparent glass substrate.

Surface electrical resistance at 4 points between the center point of each side of the transparent conductive film and the center point of the transparent conductive film using a resistivity meter ("Loresta MCP-T610" manufactured by Mitsubishi Chemical Analytech Co., Ltd.) The value was measured. The average value of the surface electrical resistance values at the four locations was taken as the measured value of the surface electrical resistance value after storage. Storage stability of the composition for forming a transparent conductive film when the change rate calculated using the following formula from the surface electrical resistance value after storage and the initial surface electrical resistance value measured previously is 5% or less Is “good”, the storage stability is “good” when it is 6% or more and less than 10%, and the storage stability is “bad” when it is 10% or more.
Rate of change (%) = [(surface electrical resistance value after storage−initial surface electrical resistance value) / initial surface electrical resistance value] × 100

  The compositions of the transparent conductive film forming compositions A to O produced in Examples 1 to 8 and Comparative Examples 1 to 7 are shown in Tables 1 to 4. Moreover, each said evaluation result is shown in Tables 5-8.

  In Examples 1, 2, and 5-8 using the transparent conductive film forming compositions A to B and E to H, the change rate of the surface electrical resistance value before and after the coating was stored for 7 days in a 25 ° C. environment However, it was 5% or less with respect to the initial surface electric resistance value, and the evaluation of “good” was obtained. In addition, the transparent conductive substrate formed using the transparent conductive film forming compositions A to B and E to H, even when formed with a spin coater or a bar coater, the initial surface electrical resistance value, the surface roughness, Evaluation of “good” was obtained for all items of haze value.

  In Example 3 using the composition C for forming a transparent conductive film, since the ketone solvent in the solvent A is small, the change rate of the surface electric resistance value is 8%, and the storage stability of the composition is “good”. It became evaluation of. In addition, both the transparent conductive substrate formed with a transparent conductive film using a spin coater and the transparent conductive substrate formed with a transparent conductive film using a bar coater have initial surface electrical resistance values of 11,000 Ω / square, It was 200Ω / square, which was evaluated as “good”.

  In Example 4 using the composition D for forming a transparent conductive film, since the ketone solvent in the solvent B is small, the change rate of the surface electric resistance value is 6%, and the storage stability of the composition is “good”. It became evaluation of. Moreover, the initial surface electrical resistance values are 12,000 Ω / square and 11,800 Ω / square, respectively, for the transparent conductive substrate on which the transparent conductive film is formed by either the spin coater or the bar coater. It became. Further, the haze values of the transparent conductive substrate were 1.2% and 1.2%, respectively, and the evaluation was “good”.

  On the other hand, in Comparative Example 1 using the transparent conductive film forming composition I, the transparent conductive substrate on which the transparent conductive film is formed using a spin coater has a large amount of the solvent A having a relative evaporation rate of 1 or more. The solvent was quickly dried from the composition, and the initial surface electrical resistance value and the haze value were 13,500 Ω / square and 1.2%, respectively, which were evaluated as “good”. Moreover, the surface roughness was evaluated as “bad” at 8.5 nm.

  In Comparative Example 2 using the composition J for forming a transparent conductive film, the transparent conductive substrate on which the transparent conductive film was formed using a spin coater had a solvent A having a relative evaporation rate of 1 or more as compared with Comparative Example 1. In many cases, the drying of the solvent from the composition is faster than that of Comparative Example 1, so that the initial surface electrical resistance value is evaluated as “bad” at 15,500Ω / square, and the surface roughness is also evaluated as “bad” at 9.6 nm. The haze value was 2.3%, which was evaluated as “bad”.

  In Comparative Example 3 using the composition K for forming a transparent conductive film, since the amount of the solvent B having a relative evaporation rate of 1 or less is too much, the change rate of the surface electrical resistance value is 7%, and the storage stability of the composition is improved. It was evaluated as “good”. In addition, the transparent conductive substrate on which the transparent conductive film was formed by any of the spin coater and bar coater coating methods was evaluated as “bad” with initial surface electrical resistance values of 17,200 Ω / square and 17,500 Ω / square, respectively. The surface roughness was evaluated as “good” at 7.3 nm and 7.8 nm, respectively, and the haze values were evaluated as “good” at 1.7% and 1.8%, respectively.

  In Comparative Example 4 using the composition L for forming a transparent conductive film, since the ketone solvent in the solvent B is 0, the change rate of the surface electrical resistance value is 20%, and the storage stability of the composition is “ It was evaluated as “bad”. In addition, the transparent conductive substrate on which the transparent conductive film is formed by any coating method of spin coater or bar coater has an initial electric resistance value of 23,000 Ω / square, 22,500 Ω / square, and a surface roughness of 11.5 nm, respectively. 11.0 nm and haze values were 2.8% and 2.6%, respectively, and all were evaluated as “bad”.

  In Comparative Example 5 using the composition M for forming a transparent conductive film, the solid content concentration of the composition was high, so that the viscosity increased and sufficient dispersion could not be obtained, and the rate of change in the surface electrical resistance value was 8%. The storage stability of the product was evaluated as “good”. In addition, the transparent conductive substrate on which the transparent conductive film is formed by any coating method of spin coater or bar coater has an initial electric resistance value of 16,200 Ω / square, 16,300 Ω / square, and a surface roughness of 8.8 nm, respectively. 8.4 nm and haze values were 2.3% and 2.1%, respectively, which were evaluated as “bad”, respectively.

  In Comparative Example 6 using the composition N for forming a transparent conductive film, the transparent conductive substrate on which the transparent conductive film was formed using a spin coater had a low solid content concentration, so that the drying time was reduced when forming the coating film. The initial surface electrical resistance value and haze value were 15,200 Ω / square and 2.3%, respectively, which were evaluated as “bad”. Further, the surface roughness was 7.1 nm, and the evaluation was “good”. Further, the haze value of the transparent conductive substrate on which the transparent conductive film was formed by the bar coater coating method was 1.5%, which was evaluated as “good”.

  In Comparative Example 7 using the transparent conductive film-forming composition O, since the ketone solvent in the solvent A is 0, the change rate of the surface electrical resistivity is 12%, and the storage stability of the composition is “ It was evaluated as “bad”. In addition, the transparent conductive substrate on which the transparent conductive film is formed by any of the spin coater and bar coater coating methods has an initial electric resistance value of 21,000 Ω / square, 21,200 Ω / square, and a surface roughness of 8.8 nm, respectively. , 8.2 nm, and haze values were 2.1% and 2.1%, respectively.

  The present invention can be implemented in other forms than the above without departing from the spirit of the present invention. The embodiments disclosed in the present application are merely examples, and the present invention is not limited thereto. The scope of the present invention is construed in preference to the description of the appended claims rather than the description of the above specification, and all modifications within the scope equivalent to the claims are construed in the scope of the claims. It is included.

Claims (7)

A transparent conductive film forming composition comprising transparent conductive particles, a binder resin, and a solvent,
The solid content concentration of the composition for forming a transparent conductive film is 20 to 50% by mass,
The solvent includes a solvent A having a relative evaporation rate of 1 or more when the evaporation rate of butyl acetate is 1, and a solvent B having a relative evaporation rate of less than 1.
The mass ratio of the solvent A and the solvent B is solvent A: solvent B = 40: 60 to 5:95,
Both of the solvent A and the solvent B contain at least a ketone solvent, the composition for forming a transparent conductive film. The content of the ketone solvent in the solvent A is 90% by mass or more based on the total amount of the solvent A,
The composition for forming a transparent conductive film according to claim 1, wherein the content of the ketone solvent in the solvent B is 70% by mass or more based on the total amount of the solvent B.   The composition for forming a transparent conductive film according to claim 1 or 2, wherein the ketone solvent having a relative evaporation rate of 1 or more is at least one selected from the group consisting of acetone, methyl ethyl ketone, and methyl isobutyl ketone.   The ketone solvent having a relative evaporation rate of less than 1 is selected from the group consisting of cyclopentanone, cyclohexanone, cycloheptanone, diisobutyl ketone, 2-heptanone, methyl isoamyl ketone, methyl-n-propyl ketone, and isophorone. It is at least 1 sort (s), The composition for transparent conductive film formation of any one of Claims 1-3. A transparent conductive substrate comprising a transparent substrate and a transparent conductive film disposed on the transparent substrate,
The said transparent conductive film was formed using the composition for transparent conductive film formation of any one of Claims 1-4, The transparent conductive substrate characterized by the above-mentioned.   The transparent conductive substrate according to claim 5, wherein the total light transmittance is 75% or more.   The transparent conductive substrate according to claim 5 or 6, wherein the haze value is 2% or less.